1. Field of the Invention
The present invention relates to an organic light emitting display and image compensation method, and more particularly, the present invention relates to an organic light emitting display and image compensation method for improving the Long Range Uniformity (LRU) of the output image by displaying the identical image when the identical image is input to each pixel, by measuring luminance, chromaticity coordinates and color temperature after an organic light emitting display panel is fabricated, by storing the compensation values thereof in a memory in the form of a look-up table in advance, and by compensating one of a power supply voltage, a data voltage and a light emission time using the compensation values.
2. Description of the Related Art
In general, the video characteristics of the organic light emitting display, (for example, luminance, chromaticity coordinate and color temperature), include electrical characteristics, thin film transistor characteristics and organic light emitting diode characteristics.
An organic light emitting diode may be composed of an anode, an organic layer and a cathode. The organic layer may be composed of an emitting layer (EML) that emits light by forming an exciton when an electron and a hole contact each other, an electron transport layer (ETL) for transporting the electron, and a hole transport layer (HTL) for transporting the hole. An electron injecting layer (EIL) may be formed on one side of the electron transport layer, and a hole injecting layer (HIL) may further be formed on one side of the hole transport layer. Furthermore, in a phosphorescent organic light emitting diode, a hole blocking layer may be selectively formed between the emitting layer and the electron transport layer, and an electron blocking layer may be selectively formed between the emitting layer and the hole transport layer.
The resistance of an anode and a cathode of the organic light emitting diode, a voltage drop (IR drop) in the power line (ELVDD, ELVSS) and a degree of uniformity when the organic light emitting diode is deposited on an organic thin film layer, etc. are known factors in the degrading of a Long Range Uniformity (LRU) of the video characteristics.
To reduce this problem, many others have tried to improve the material of the anode and cathode of the organic light emitting diode, to increase the mobility of electrons and holes by laminating organic thin film layers, and to reduce the resistance of the power line by adjusting its width, depth, etc.
However, in spite of these efforts, the LRU of the video is still main issue in the product development and it is not fully improved. That is, there is a deviation of luminance, chromaticity coordinate and color temperature at each pixel even if the material and process are improved as described above, and thus the LRU as well as the short range uniformity are degraded.
In other words, there is a problem that the reliability of the display is reduced and the life time of the display is shortened, since a different image is displayed even when the identical image is input to each pixel with time.